1. Field of the Invention
The present invention relates generally to snowmobiles, and more particularly to mono-shock suspensions applicable to snowmobiles.
2. Description of the Related Art
In snowmobiles, mono-shock suspensions are generally known as a technology utilized for absorbing shocks generated from impacts with the snow surface. For example, according to FIG. 3 of U.S. Pat. No. 5,904,216, suspension link 72 and levers 83 are connected to tube 73, and an end portion of shock absorber 77 is connected to levers 83. In addition, links 88 and bracket arms 92 are connected to tubular member 89, and another end portion of shock absorber 77 is connected to bracket arms 92. Tube 73 and tubular member 89 are respectively fixed to frame assembly 53, and suspension link 72 and bracket arms 92 are each indirectly connected to guide rails 63. Therefore, shock absorber 77 is capable of absorbing and transferring shocks from guide rails 63 to frame assembly 53.
In the above-described mono-shock suspension, levers 83 are always positioned below tube 73, and shock absorber 77 is fixed to the lower end of levers 83. Therefore, when guide rails 63 and frame assembly 77 approach each other due to an impact on guide rails 63, the height of the lower end of shock absorber 77 and that of guide rails 63 become substantially equal, as shown in FIG. 4 of U.S. Pat. No. 5,904,216.
On the other hand, when the impact on guide rails 63 is small, the height between the lower end of shock absorber 77 and guide rails 63 differs significantly, as shown in FIG. 3 of U.S. Pat. No. 5,904,216. Therefore, in the above-described mono-shock suspension, the movable range of the lower end of shock absorber 77 is large, and a large stroke can be maintained in shock absorber 77.
However, it is difficult to maintain the rigidity of the vehicle in the case where the movable range of shock absorber 77 is large. Specifically, guide rails 63 are respectively provided on the left and right of the vehicle, and the rigidity of the vehicle should be maintained by connecting each guide rail 63 by a connecting member. However, according to the above-described technology, the lower end of shock absorber 77 is capable of approaching the region between the left and right guide rails 63, and hence the connecting member connecting each guide rail 63 cannot be arranged in a desirable position.